NFHS and NCAA Men's Rules have ajudicated this play as a Double Foul originally per a Note in the Rules and later through an Casebook Play (NFHS)/Approved Ruling (NCAA Men's) for well over 60 years. While the NCAA Women's Rules have always (with apologies to the late J. Dallas Shirely) ajudicated this as either a Block or a Charge, in the manner that Bob Jenkins as stated, originally through a Note in its CCA Officials Manual and now through an Approved Ruling.
I have held (since the 1971-72 school year when I first started officiating) that the NFHS/NCAA Men's Ruling is 100% incorrect and the NCAA Women's Ruling is 100% correct and the NCAA Women's protocol for the Play is the correct to handle such a Play.
By Rule, it is impossible to have a 'blarge'. Either: (a) B1 has Obtained (NFHS/NCAA Women's)/Established (NCAA Men's) a LGP or (b) B1 has NOT Obtained (NFHS/NCAA Women's)/Established (NCAA Men's) a LGP. (a) and (b) can NOT happen simultaneously! It is 100% impossible for (a) and (b) to happen simultaneously!
If (a) occurs then A1 has committed a Charging Foul and if (b) occurs then B1 has committed a Blocking Foul.
And for the 46 years that I officiated boys'/girls' JrHS/HS basketball and for the 15 years that I officiated men's jr. college basketball I pre-gamed 'blarges' out of existence in my games.
MTD, Sr.